Centrifugal pulp screen



G. 'F. SHEVLIN. CENTHIFUGAL PULP SCREEN.

APPLICATION FILED AUG. 4| I921.

Patented Nov. 21, 11922 2 SHEETS-SHEET l- G. F. SHEVLIN. CENTRIFUGAL PULP SCREEN. APPLICATION FILED AUG. 4. 1921.

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Application filed August/l, 1921. Serial No. 489,874.

To all whom it may concern Be it known that I, GEORGE F. SnEvuN, a citizen 'of the United States, residing at Glens Falls, in the county of Warren and State of New York, have invented an Improvement in Centrifugal Pulp Screens, of which the following is a specification.

This invention relates to a centrifugal pulp screen used in screening pulp and paper stock, and more particularly to the pulp or paper stock distributor or runner.

Heretofore, it has been customary to so construct the distributor or runner of a centrifugal pulp screen as to provide the same with a plurality of compartments into which the pulp and paper stock are suitably fed and from which the stock is delivered through slots or other openings in the walls of the compartment to suitable blades from and by which through the centrifugal action made possible byrthe rapid revolution of the distributor or runner the pulp or .paper stock is forcibly thrown against the screen of the separator. I am aware that heretofore in order to prevent the heavier portions of the pulp or paper stock from accumulating at the bottom of the distributor or runner the well into which the pulp or stock is delivered is made with discharge passages at the bottom thereof. In these and other types of distributors or runners forcentrifugal pulp screens with which I have become acquainted the discharge of the pulp or paper stock has been accomplished in substantially the same manner throughout the entire length of the distributor and in view of the different consistency of the pulp or stock in different parts or at different elevations of the dis tributor I have found it possible to obtain more efficient results by employing a different means for distributing the lighter or more finely divided portions of the stock at the upper part of the distributor than those employed for delivering the heavier portions of the stock at the bottom or in the lower portions of the distributor. In the lower portions of the distributor I have found that the radially placed blades extending from the usual cylindrical body of the distributor answer the purposes as well as any other form, but with the lighter portions of the pulp or stock at the top of the distributor lhave also found that by associating a curved vane with each of the blades that those portions of the lighter stock delivered fIIOIIh the u er art of the (llStIlblltOI'. are ejected l ltll greater force and a consequent more efficient separation or screening is produced. 1

In carry ng out the invention, therefore the stock distributor or runner made in ac cordance with my invention preferably comprises a hub and a cylindrical member or barrel connected thereto by radially disposed blades extending between the same and continuing exteriorly of the cylindrical member, together with a vane preferably having a curved surface associated with each of the blades exteriorly of the cylindrical member and extending from the top of the distributor to a position approximately midway of its length. The walls of the cylndrical member are provided with a series of open ngs running along the inner end of each of the said vanes and to a position below the same, while below the vanes each portion of the walls of the cylindrical member comprising one of the compartments thereof is provided With a series of openings at the opposite side of the compartment and extending below the lower edge of the vane. The distributor or runner is also provided with a top plate and preferably with a curved bottom plate spaced from the lower ends of the cylindrical inemlJGI' lll order to permit of the discharge of the heavier parts of the pulp or stock which, by the action of the curved surface of the bottom plate, is delivered to the screen or permitted to pass to the trough or piping through which the slivers are discharged. In the drawing:

Fig. 1 is an elevation illustrating my improved distributor or runner.

Fig. 2 is a transverse section on line 2-2, Fig. l,

Fig. 8 is a sectional elevation taken on line 33, Fig. 4,

Fig. 4 is a plan viewof the distributor. Referring particularly to the drawing the distributor made inaccordance with my present invention preferably comprises a hub 10 adapted by any suitable means to be secured to a shaft by which the distributor is revolved. The hub-1O is connected to the customary cylindrical or barrel member 11 by a series of radially placed blades 12 extending between the hub and the barrel and dividing the space within the barrel member into a corresponding number of compartments into which the pulp or paper stock to the larger and heavier tially midway the length of the distributor, although the precise position at which these vanes terminate is immaterialto the present invention. As clearly indicated in Figs. '2

and 4.- of the drawing each vane extends from the outer surface of the barrel member ad jacent one of the exterior blades 14 to the outer edge of the adjacent blade 14 and the outer face of each of the vanes is preferably curved.

The distributor also includes a bottom plate which as illustrated'is concavo-convex and extends from the hub 10 and has a diarneter which is substantially the same as that of the exterior blades 14. In that por- ,tion of the wall of the barrel member defining each compartment there is a series of outlet holes 18 runningadjacentthe blade letat which is the inner end of the corresponding vane so that the lighter portions of the pulp or paper stock which are delivered through these outlet'openingsis caused to flow over the curved face of the "vane and by the centrifugal action of the distributor to be forcibly thrown against the screen of the separator. This series of outlet holes 18 extends below the loweredge of the vane and there is also a transverse series of holes in each of the walls of the barrel member as indicated at 19, while on the opposite side of each of these walls of the barrel member there is a series of holes 20 extending longitudinally beneath the lower ec ge of the corresponding vane.

From the drawing it will also be observed that there are spaces 21 between the inner or lower end of the cylindrical or barrel member and the upper surface of the bottom plate of the distributor as indicated at 21 in order that the larger and heavier portions of the pulp and paper stock which cannot pass through the openings 18, 19 and 20- may be delivered to the bottom plate and by the action of the bottom plate delivered from the separator.

From the foregoing it that the finer or lighter particles of the pulp or stock which are always at the top of the distributor will pass through the upper openings 18 and over t-he-faces'of the vanes 15 in being thrown against the screen, while portions of the pulp or stock pass through the lower openings 18 or those openings 18 below the lower edges of the vanes 15 as well as through the openings 19 and 20, being acted upon bythe porproximately midway the length will be understood tions of the blades 14 lying below the lower edges of the vanes 15 and those portions of the pulp or paper stock which do not or cannot passthrough any of the openings 18, 19 and 20 will pass through the spaces 21 and willbe ejected from the distributor by the lower or bottom plate 17. By this form of distributor, dueto; the blades 15 and the increased number of openings and the consequent outletsurface belowthe same, I have found that there is a more even distribution of the stock or pulp effected than in other forms of distributors with which I am acquainted.

I claim as my invention:

v 1. In a centrifugal pulp screen, a stock distributor comprising a hub, a cylindrical member, blades extending from the hub to and beyond the cylindr-ical member, and a plurality of vanes each associated with the cylindrical member and extending between the same and the outer edge of one of the said blades.

2. In a centrifugal pulp screen, a stock distributor comprising a hub, a barrel member, radiallyplaced blades extending between the hub and barrel member and continuing exteriorly of the said bar-relmemher, and a plurality of vanes each extending between an outer portion of the barrel member and the edge of one of the blades and from the upper part of the distributor to a position substantially midway thelength of the same.

3. In a centrifugal pulp screen, a stock distributor comprising a hub, a barrel member, series of blades extending between the hub. and the barrel member dividing the same into compartments towhich the pulp or stock is delivered, a plurality of blades extending radially from the said barrel member, and a corresponding number of vanes each extending from the outer surface of the barrel member adjacent one of the exterior blades to the outer edge of the next adjacent exterior blade and also from the top of the distributor to a position apof the same,

there being a series of discharge openings in the wall of the barrel adjacent the inner end of each vane and another series of discharge openings in the wall of'the barrel extending below each of the vanes.

4. In a centrifugal pulp screen, a stockdistributor comprising a hub, a barrel member, series of blades extending between the hub and the barrel member dividing the same into compartments to which the'pul or stock is delivered, a plurality ofblades extending radially from the said barrel member, and a corresponding number of vanes each face of the the exterior next. adjacent exterior blade and also from extending from the outer surbarrel member adjacent one of blades to the outer edge of the the top of the distributor to a position ap proximately midway the length of the same, there being a series of discharge openings in the wall of the barrel ad acent the inner end of each vane and another series of discharge openings in the wall of the barrel extending below each of the vanes, there being also series of openings extending transversely across the wall of the barrel member below each of the said vanes.

5. In a centrifugal pulp screen, a stock distributor comprising a hub, a barrel member, a plurality of blades extending radially from the said hub to the said barrel member dividing the same into a plurality of compartments, a corresponding number of blades extending radially and in alignment with the aforesaid blades exteriorly of the said barrel member, a top plate, a bottom plate spaced from the lower end of the said barrel member, and a plurality of vanes each extending from the outer surface of the barrel member adjacent an exterior blade to the edge of the next adjacent exterior blade and also from the top plate to a position approximately midway the length of the distributor.

6. In a centrifugal pulp screen, a stock distributor comprising a hub, a barrel member, a plurality of blades extending radially from the said hub to the said barrel member dividing the same into a plurality of compartments, a corresponding number of blades extending radially and in alignment with the aforesaid blades exteriorly of the said barrel member, a top plate, a concaveconvex bottom plate extending from the said hub and spaced from the lower end of the said barrel member, and a plurality of vanes each extending from the outer surface of the barrel member adjacent an exterior blade to the edge of the next adjacent exterior blade and also from the top plate to a position approximately midway the length of the distributor, there being series of outlet openings in the wall of the barrel member between each of the said exterior blades.

7. In a centrifugal pulp screen, a stock distributor comprising a hub, a barrel member, a plurality of blades extending radially from the said hub to the said barrel member dividing the same into a plurality of compartments, a corresponding number of blades extending radially and in alignment with the aforesaid blades exteriorly of the said barrel member, a top plate, a concavo-convex bottom plate extending from the said hub and spaced from the lower end of the said barrel member, a plurality of vanes each extending from the outer surface of the barrel member adjacent an exterior blade to the edge of the next adjacent exterior blade and also from the top plate to a position approximately midway the length of the distributor, there being in each section of the Wall of the barrel member a series of openings extending longitudinally thereof and along the inner end of the corresponding vane, and a series of openings in the opposite portion of each wall section of the barrel member extending longitudinally below the lower edge of the corresponding vane and a series of openings extending transversely between the aforesaid series of openings and also below the lower edge of the corresponding vane.

Signed by me this 29th day of July, 1921.

GEO. l. SHEVLIN. 

